tests: activate misspelled gdb-check in function-arg-initialization.rs

In 9253e12 a bunch of `gdbr-check` (for `rust-gdb`) and
`gdbg-check` (for plain `gdb`) was added. But in two places the author
accidentally wrote `gdbt-check` instead. This commit fixes this typo.

Author: Enselic

tests/debuginfo/function-arg-initialization.rs

@@ -6,8 +6,9 @@
 // function name.
 
 //@ min-lldb-version: 1800
-//@ compile-flags:-g -Zmir-enable-passes=-SingleUseConsts
+//@ compile-flags:-g -Zmir-enable-passes=-SingleUseConsts -Copt-level=0
 // SingleUseConsts shouldn't need to be disabled, see #128945
+// Disable optimizations to avoid `<optimized out>` prints
 //@ disable-gdb-pretty-printers
 //@ ignore-backends: gcc
 
@@ -26,9 +27,9 @@
 
 // NON IMMEDIATE ARGS
 // gdb-command:print a
-// gdbt-check:$4 = function_arg_initialization::BigStruct {a: 3, b: 4, c: 5, d: 6, e: 7, f: 8, g: 9, h: 10}
+// gdb-check:$4 = function_arg_initialization::BigStruct {a: 3, b: 4, c: 5, d: 6, e: 7, f: 8, g: 9, h: 10}
 // gdb-command:print b
-// gdbt-check:$5 = function_arg_initialization::BigStruct {a: 11, b: 12, c: 13, d: 14, e: 15, f: 16, g: 17, h: 18}
+// gdb-check:$5 = function_arg_initialization::BigStruct {a: 11, b: 12, c: 13, d: 14, e: 15, f: 16, g: 17, h: 18}
 // gdb-command:continue
 
 // BINDING