[RISCV] Add testcase for -mcmodel= (#107816)

This is a pre-commit test for #107817

Author: tclin914

clang/test/Driver/riscv-mcmodel.c

@@ -0,0 +1,14 @@
+// RUN: %clang --target=riscv32 -### -c -mcmodel=small %s 2>&1 | FileCheck --check-prefix=SMALL %s
+// RUN: %clang --target=riscv64 -### -c -mcmodel=small %s 2>&1 | FileCheck --check-prefix=SMALL %s
+
+// RUN: %clang --target=riscv32 -### -c -mcmodel=medlow %s 2>&1 | FileCheck --check-prefix=SMALL %s
+// RUN: %clang --target=riscv64 -### -c -mcmodel=medlow %s 2>&1 | FileCheck --check-prefix=SMALL %s
+
+// RUN: %clang --target=riscv32 -### -c -mcmodel=medium %s 2>&1 | FileCheck --check-prefix=MEDIUM %s
+// RUN: %clang --target=riscv64 -### -c -mcmodel=medium %s 2>&1 | FileCheck --check-prefix=MEDIUM %s
+
+// RUN: %clang --target=riscv32 -### -c -mcmodel=medany %s 2>&1 | FileCheck --check-prefix=MEDIUM %s
+// RUN: %clang --target=riscv64 -### -c -mcmodel=medany %s 2>&1 | FileCheck --check-prefix=MEDIUM %s
+
+// SMALL: "-mcmodel=small"
+// MEDIUM: "-mcmodel=medium"