[gdb/testsuite] allow more registers in gdb.base/jit-reader.exp

Fixes jit-reader test failures on systems that have more registers than
expected by the current condition.

On Intel i9-7920X the following extra registers are printed:

k0             0x0                 0
k1             0x0                 0
k2             0x0                 0
k3             0x0                 0
k4             0x0                 0
k5             0x0                 0
k6             0x0                 0
k7             0x0                 0

gdb/testsuite/ChangeLog:

2020-02-18  Mihails Strasuns  <mihails.strasuns@intel.com>

	* gdb.base/jit-reader.exp: Relax register output check.

gdb/testsuite/gdb.base/jit-reader.exp

@@ -66,7 +66,8 @@ proc info_registers_current_frame {sp} {
     set any "\[^\r\n\]*"
 
     set neg_decimal "-?$decimal"
-    gdb_test "info registers" \
+
+    set expected \
 	[multi_line \
 	     "rax            $hex +$neg_decimal" \
 	     "rbx            $hex +$neg_decimal" \
@@ -93,6 +94,11 @@ proc info_registers_current_frame {sp} {
 	     "fs             $hex +$neg_decimal" \
 	     "gs             $hex +$neg_decimal" \
 	    ]
+
+    # There may be more registers.
+    append expected ".*"
+
+    gdb_test "info registers" $expected
 }
 
 proc jit_reader_test {} {
@@ -170,7 +176,8 @@ proc jit_reader_test {} {
 
 		# Since the JIT unwinder only provides RIP/RSP/RBP,
 		# all other registers should show as "<not saved>".
-		gdb_test "info registers" \
+
+		set expected \
 		    [multi_line \
 			 "rax            <not saved>" \
 			 "rbx            <not saved>" \
@@ -198,6 +205,11 @@ proc jit_reader_test {} {
 			 "gs             <not saved>" \
 			]
 
+		# There may be more registers.
+		append expected ".*"
+
+		gdb_test "info registers" $expected
+
 		# Make sure that "info frame" doesn't crash.
 		gdb_test "info frame" "Stack level 1, .*in main.*"