cmd/go: remove limits on parallel tasks in the Go command for iOS

Ther darwin/arm{,64} exec wrapper now limits the number of concurrent
executions to 1, so remove the higher level parallel task limit from
the Go command.

Change-Id: Id84f65c3908305bde0452b3c8db6df8c5a8881bb
Reviewed-on: https://go-review.googlesource.com/21100Reviewed-by: David Crawshaw <crawshaw@golang.org>

src/cmd/go/alldocs.go

@@ -86,8 +86,7 @@ and test commands:
 	-p n
 		the number of programs, such as build commands or
 		test binaries, that can be run in parallel.
-		The default is the number of CPUs available, except
-		on darwin/arm which defaults to 1.
+		The default is the number of CPUs available.
 	-race
 		enable data race detection.
 		Supported only on linux/amd64, freebsd/amd64, darwin/amd64 and windows/amd64.
@@ -577,6 +576,7 @@ syntax of package template.  The default output is equivalent to -f
         CXXFiles       []string // .cc, .cxx and .cpp source files
         MFiles         []string // .m source files
         HFiles         []string // .h, .hh, .hpp and .hxx source files
+        FFiles         []string // .f, .F, .for and .f90 Fortran source files
         SFiles         []string // .s source files
         SwigFiles      []string // .swig files
         SwigCXXFiles   []string // .swigcxx files
@@ -586,6 +586,7 @@ syntax of package template.  The default output is equivalent to -f
         CgoCFLAGS    []string // cgo: flags for C compiler
         CgoCPPFLAGS  []string // cgo: flags for C preprocessor
         CgoCXXFLAGS  []string // cgo: flags for C++ compiler
+        CgoFFLAGS    []string // cgo: flags for Fortran compiler
         CgoLDFLAGS   []string // cgo: flags for linker
         CgoPkgConfig []string // cgo: pkg-config names
 
@@ -1563,6 +1564,7 @@ Here is another example where the ordering of the output is ignored:
 		for _, value := range Perm(4) {
 			fmt.Println(value)
 		}
+
 		// Unordered output: 4
 		// 2
 		// 1

src/cmd/go/build.go

@@ -65,8 +65,7 @@ and test commands:
 	-p n
 		the number of programs, such as build commands or
 		test binaries, that can be run in parallel.
-		The default is the number of CPUs available, except
-		on darwin/arm which defaults to 1.
+		The default is the number of CPUs available.
 	-race
 		enable data race detection.
 		Supported only on linux/amd64, freebsd/amd64, darwin/amd64 and windows/amd64.
@@ -145,17 +144,6 @@ func init() {
 
 	addBuildFlags(cmdBuild)
 	addBuildFlags(cmdInstall)
-
-	if buildContext.GOOS == "darwin" {
-		switch buildContext.GOARCH {
-		case "arm", "arm64":
-			// darwin/arm cannot run multiple tests simultaneously.
-			// Parallelism is limited in go_darwin_arm_exec, but
-			// also needs to be limited here so go test std does not
-			// timeout tests that waiting to run.
-			buildP = 1
-		}
-	}
 }
 
 // Flags set by multiple commands.