test: Add some missing x86_64-linux-* triples to llvm_targets.

Author: alexrp

test/llvm_targets.zig

@@ -350,6 +350,10 @@ const targets = [_]std.Target.Query{
     .{ .cpu_arch = .x86_64, .os_tag = .ios, .abi = .macabi },
     .{ .cpu_arch = .x86_64, .os_tag = .ios, .abi = .simulator },
     .{ .cpu_arch = .x86_64, .os_tag = .linux, .abi = .android },
+    .{ .cpu_arch = .x86_64, .os_tag = .linux, .abi = .gnu },
+    .{ .cpu_arch = .x86_64, .os_tag = .linux, .abi = .gnux32 },
+    .{ .cpu_arch = .x86_64, .os_tag = .linux, .abi = .musl },
+    .{ .cpu_arch = .x86_64, .os_tag = .linux, .abi = .muslx32 },
     .{ .cpu_arch = .x86_64, .os_tag = .linux, .abi = .none },
     .{ .cpu_arch = .x86_64, .os_tag = .linux, .abi = .ohos },
     .{ .cpu_arch = .x86_64, .os_tag = .macos, .abi = .none },