Deprecate group_static_libs property

We now default to lld for platform builds, removing all need for this
property.  For more details, see "Effecient archive file handling" in
https://lld.llvm.org/NewLLD.html#key-concepts

Bug: 189475744
Test: Manual build succeeds
Change-Id: If1104d68b13de8c7afab35c1741a68f64394b448

cc/linker.go

@@ -86,8 +86,7 @@ type BaseLinkerProperties struct {
 	// compiling crt or libc.
 	Nocrt *bool `android:"arch_variant"`
 
-	// group static libraries.  This can resolve missing symbols issues with interdependencies
-	// between static libraries, but it is generally better to order them correctly instead.
+	// deprecated and ignored because lld makes it unnecessary. See b/189475744.
 	Group_static_libs *bool `android:"arch_variant"`
 
 	// list of modules that should be installed with this module.  This is similar to 'required'
@@ -543,10 +542,6 @@ func (linker *baseLinker) linkerFlags(ctx ModuleContext, flags Flags) Flags {
 
 	flags.Global.LdFlags = append(flags.Global.LdFlags, toolchain.ToolchainLdflags())
 
-	if Bool(linker.Properties.Group_static_libs) {
-		flags.GroupStaticLibs = true
-	}
-
 	// Version_script is not needed when linking stubs lib where the version
 	// script is created from the symbol map file.
 	if !linker.dynamicProperties.BuildStubs {