Fix shell.Exec calls in git.go

In this CL:
https://swiftshader-review.googlesource.com/c/SwiftShader/+/69010
The signature of the Exec function was changed to add stdin.

This change wasn't applied to the git.go file. This CL fixes that by
adding "" as the stdin argument for all shell.Exec calls in git.go

Bug: b/201453797
Change-Id: I0d7ad5bb142e2fbbb54df6286a99b97860122992
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/69208
Tested-by: Alexis Hétu <sugoi@google.com>
Presubmit-Ready: Alexis Hétu <sugoi@google.com>
Commit-Queue: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/tests/regres/git/git.go b/tests/regres/git/git.go
index 82db614..b7a3e43 100644
--- a/tests/regres/git/git.go
+++ b/tests/regres/git/git.go
@@ -165,7 +165,7 @@
 
 // FetchRefHash returns the git hash of the given ref.
 func FetchRefHash(ref, url string) (Hash, error) {
-	out, err := shell.Exec(gitTimeout, exe, "", nil, "ls-remote", url, ref)
+	out, err := shell.Exec(gitTimeout, exe, "", nil, "", "ls-remote", url, ref)
 	if err != nil {
 		return Hash{}, err
 	}
@@ -190,7 +190,7 @@
 	if at == "" {
 		at = "HEAD"
 	}
-	out, err := shell.Exec(gitTimeout, exe, "", nil, "log", at, "--pretty=format:"+prettyFormat, fmt.Sprintf("-%d", count), path)
+	out, err := shell.Exec(gitTimeout, exe, "", nil, "", "log", at, "--pretty=format:"+prettyFormat, fmt.Sprintf("-%d", count), path)
 	if err != nil {
 		return nil, err
 	}
@@ -199,7 +199,7 @@
 
 // Parent returns the parent ChangeList for cl.
 func Parent(cl ChangeList) (ChangeList, error) {
-	out, err := shell.Exec(gitTimeout, exe, "", nil, "log", "--pretty=format:"+prettyFormat, fmt.Sprintf("%v^", cl.Hash))
+	out, err := shell.Exec(gitTimeout, exe, "", nil, "", "log", "--pretty=format:"+prettyFormat, fmt.Sprintf("%v^", cl.Hash))
 	if err != nil {
 		return ChangeList{}, err
 	}
@@ -224,7 +224,7 @@
 
 // Show content of the file at path for the given commit/tag/branch.
 func Show(path, at string) ([]byte, error) {
-	return shell.Exec(gitTimeout, exe, "", nil, "show", at+":"+path)
+	return shell.Exec(gitTimeout, exe, "", nil, "", "show", at+":"+path)
 }
 
 const prettyFormat = "ǁ%Hǀ%cIǀ%an <%ae>ǀ%sǀ%b"