make,builder: incorporate feedback from code review on Go 1.15 update

Signed-off-by: deadprogram <ron@hybridgroup.com>

Makefile

@@ -346,7 +346,7 @@ endif
 	@$(MD5SUM) test.elf
 
 wasmtest:
-	$(GO) test -buildmode exe ./tests/wasm
+	$(GO) test ./tests/wasm
 
 build/release: tinygo gen-device wasi-libc
 	@mkdir -p build/release/tinygo/bin

builder/config.go

@@ -26,7 +26,7 @@ func NewConfig(options *compileopts.Options) (*compileopts.Config, error) {
 		return nil, fmt.Errorf("could not read version from GOROOT (%v): %v", goroot, err)
 	}
 	if major != 1 || minor < 11 || minor > 15 {
-		return nil, fmt.Errorf("requires go version 1.11 thru 1.15, got go%d.%d", major, minor)
+		return nil, fmt.Errorf("requires go version 1.11 through 1.15, got go%d.%d", major, minor)
 	}
 	clangHeaderPath := getClangHeaderPath(goenv.Get("TINYGOROOT"))
 	return &compileopts.Config{