Merge bitcoin/bitcoin#30464: test, refactor: Fix MSVC warning C4101 "unreferenced local variable"

44f08786f4 test: Fix MSVC warning C4101 "unreferenced local variable" (Hennadii Stepanov)
5d25a82b9a univalue, refactor: Convert indentation tabs to spaces (Hennadii Stepanov)

Pull request description:

  This PR is split from https://github.com/bitcoin/bitcoin/pull/30454 and addresses MSVC warning [C4101](https://learn.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-3-c4101) "unreferenced local variable". The current MSVC build system in the master branch skips building univalue tests, so it is not affected.

  No behaviour changes.

ACKs for top commit:
  kevkevinpal:
    utACK [44f0878](https://github.com/bitcoin/bitcoin/pull/30464/commits/44f08786f435ed4284d39dc604c2a5fcbde9e602)
  maflcko:
    ACK 44f08786f4
  theuni:
    trivial ACK 44f08786f4.

Tree-SHA512: 661d3b40ddb4f7915de7a65ccb27a24da88ae499ce03c036099007260b0597e83738f1a3a420985b51f798ee309ade32988c6d78f4ffed401099b175a0b2025b

src/univalue/test/object.cpp

@@ -20,17 +20,17 @@
         try { \
             (stmt); \
             assert(0 && "No exception caught"); \
-        } catch (excMatch & e) { \
-	} catch (...) { \
-	    assert(0 && "Wrong exception caught"); \
-	} \
+        } catch (excMatch&) { \
+        } catch (...) { \
+            assert(0 && "Wrong exception caught"); \
+        } \
     }
 #define BOOST_CHECK_NO_THROW(stmt) { \
         try { \
             (stmt); \
-	} catch (...) { \
-	    assert(0); \
-	} \
+        } catch (...) { \
+            assert(0); \
+        } \
     }
 
 void univalue_constructor()