Remove extra checkbuild argument from ninja tools command lines

The dangling rules check was running `ninja checkbuild -t targets rule`.
This apparently worked fine with glibc, but is failing when ninja is
compiled with musl.  Musl's getopt_long is leaving "checkbuild" in argv
when calling ninja's ToolTargets, resulting in:
ninja: error: unknown target tool mode 'checkbuild'

Remove the extraneous checkbuild argument.

Bug: 190084016
Test: m checkbuild
Change-Id: I61b6475a5f7cb9d3d47232057ecfdc798864dd81

ui/build/test_build.go

@@ -51,7 +51,6 @@ func testForDanglingRules(ctx Context, config Config) {
 	executable := config.PrebuiltBuildTool("ninja")
 
 	commonArgs := []string{}
-	commonArgs = append(commonArgs, config.NinjaArgs()...)
 	commonArgs = append(commonArgs, "-f", config.CombinedNinjaFile())
 	args := append(commonArgs, "-t", "targets", "rule")